The other day I was reading a book on the mathematics of uncertainty and how understanding it can lead to better predictions, when I quite unexpectedly came across this statement on page 171:
If we let it, Bayes can be a powerful tool for updating our preconceptions in the light of new data. What Bayes doesn’t do for us, however, is suggest how we should pick those prior beliefs in the first place. There will always be some people who hold their convictions with 100 per cent certainty – think of religious fundamentalists, anti-vaxxers or climate-change deniers.
Well, I say I came across it quite unexpectedly, but that is only because I was taken by surprise that it took the author until page 171 to lay into the climate sceptic and vaccine-concerned. Normally, academics who write on matters of uncertainty have rushed to such condemnation long before they have finished their preface. It seems they just can’t help themselves. If they need to illustrate how thinking about uncertainty can go horribly wrong, they invariably pick on the climate change ‘denier’ and the anti-vaxxer. They now go together like fish, chips and holocaust deniers, although on this occasion the author preferred instead to ram his point home by invoking the example of the religious fundamentalist. The choice of comparison matters not, however, as long as the reader ‘understands’ that some people are just so irrational as to be downright unreachable. As the author puts it in the very next sentence:
What Bayes theorem tells us in these situations is that there is not a single piece of evidence, no matter how strong, that will ever shift these hardliners from their convictions.
Frankly, I don’t know where he got that particular nugget from, but certainly it wasn’t from the Reverend Bayes. There is absolutely nothing in the mathematics of Bayes’ Theory to suggest that there is a limit beyond which the strength of a prior belief can render the holder impervious to new information. That bit of prejudiced thinking comes straight from the author himself and is purely down to his prior beliefs about how climate sceptics and the vaccine-concerned came to hold their particular views. His understanding, for what it is worth, is based, as always, upon the assumption that the science is settled and that there can be no legitimate basis for ever holding out against a scientific consensus. The only possible explanation, in his mind, is that these individuals simply do not believe in updating their beliefs and have no time of day for evidence. How else could they have arrived at a position that is so remote, not only from his own, but from every one of his like-thinking academic chums?
It is obvious that the book’s author certainly knows all about the perils of the transposed conditional, but I would bet my shirt that he doesn’t appreciate that a prime example is the IPCC statement that scientists are 95% certain that over half of the recent warming has been anthropogenic. He seems to have grasped the important difference between aleatory and epistemic uncertainty, but I suspect he knows nothing regarding the extent to which that important distinction is ignored by the majority of climate scientists. He won’t be aware, I’m sure, of the profound flaws within the ONS data that were used by everyone who defends the effectiveness and safety of the Covid-19 vaccines, nor that the Office for Statistics Regulation, no less, has ruled the ONS data unsuitable for such analyses. And though he will have been as aware as anyone of the impact of false positives when testing the asymptomatic, I wonder if he took that into account when he accepted the Government’s claim that there were legions of symptom-free Covid-19 disease-spreaders roaming the streets – the assumption upon which the multi-billion pound Operation Moonshot was premised.
In fact, I just don’t think he has the faintest idea of the extent to which evidence has informed the opinions of those he so confidently dismisses as being the equivalent of religious fundamentalists.
The reality is that there are many amongst those labelled as ‘anti-vaxxers’ and ‘climate-change deniers’ who are simply trying to abide by the philosophy of the empirical sceptic and, contrary to what the author might think, they have a very healthy regard for evidence. Should the author ever deign to interact with those individuals who he has unjustifiably accused of holding views with 100 per cent certainty, it would be nice to think that he would be prepared to apply Bayes’ Rule and modify his views of them in the light of the evidence thereby revealed. But I suspect that he would prove every bit as intransigent as those he condemns. I expect that there is not a single piece of evidence, no matter how strong, that will ever shift him from his conviction that ‘anti-vaxxers’ and ‘climate-change deniers’ are just mindless fundamentalists. Despite the fact that he himself offered no evidence to support his proposition that such people are intransigent and evidence-averse, he will continue to presume that he and his enlightened colleagues are alone in understanding the laws of uncertainty and hence able to remain open-minded.
Okay, rant over.
I can now return to reading what had, until page 171, been a reasonably entertaining and informative book. I shall take on board what page 171 has taught me about the author, and like a good Bayesian I will update my prior assumptions. None of this has been enough to put me off finishing the book, but it has only entrenched my firm belief that intelligence and academic status are not sufficient to prevent the individual from hypocritically falling into a silo of thinking, informed more by bigotry than by evidence or logic.
On the transposed conditional, Prof. Norman Fenton explained how IPCC committed the fallacy in his GWPF paper.
The author, Professor Norman Fenton, shows that the authors of the Summary for Policymakers claimed, with 95% certainty, that more than half of the warming observed since 1950 had been caused by man. But as Professor Fenton explains, their logic in reaching this conclusion was fatally flawed.
“Given the observed temperature increase, and the output from their computer simulations of the climate system, the IPCC rejected the idea that less than half the warming was man-made. They said there was less than a 5% chance that this was true.”
“But they then turned this around and concluded that there was a 95% chance
that more than half of observed warming was man-made.”
This is an example of what is known as the Prosecutor’s Fallacy, in which the probability of a hypothesis given certain evidence, is mistakenly taken to be the same as the probability of the evidence given the hypothesis.
As Professor Fenton explains
“If an animal is a cat, there is a very high probability that it has four legs.
However, if an animal has four legs, we cannot conclude that it is a cat.
It’s a classic error, and is precisely what the IPCC has done.”
Professor Fenton’s paper is entitled The Prosecutor’s Fallacy and the IPCC Report.
My synopsis is https://rclutz.com/2023/09/16/ipcc-guilty-of-prosecutors-fallacy/
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Ron,
Thank you for that footnote. I had forgotten that Fenton had published at the GWPF. I note that his own website now posts articles for subscribers only.
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Sent from my iPad
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It makes no sense to pick on groups of people with a small number of absolutists, next to whom stand a large bunch of thinking people. There may be anti-vaxxers who are militantly against all vaccines. But there is a far larger group of people who are concerned about particular vaccines under particular circumstances, and who are right to be so. It is rather lazy to dismiss such concerns by labelling the wider group as beyond reason, as so often happens.
As readers of this site know, it is a major gripe of mine that nuanced arguments are readily distilled into binaries for reasons of winning rather than finding out the truth.
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Jit,
It is interesting to me that you have focused on the laziness that lies behind labelling, because I had toyed with the idea of using ‘How lazy labelling is demeaning the debate‘ as the article’s excerpt. It never ceases to amaze me how often experts who are writing on how best to think critically fail to do so themselves as soon as they reference the sceptic.
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It (transposed conditional) arises quite straightforwardly from the IPCC’s remit to report on the degree and rate of man-made climate change and what may be done about it. So like good public servants they know they mustn’t wander outside their remit. Sir John Houghton explained this to me way back in AR1 days when I was still a devout believer.
So for that reason “they” see no need to consider those terms in the Bayes formula required to transpose to the standard way of doing science which is to ask, “given the evidence what is the probability of the hypothesis”. These required terms to adjust away from “given the hypothesis, what is the probability of the evidence” include how well the observations fit an alternative explanation (like natural fluctuations) or observations that don’t fit the hypothesis (like effects that precede causes). Nowadays it’s got to the point where they do not even recognise the need as the hypothesis has become the paradigm and that lets them off the hook.
You can see this at work in those weird contortions used by WG1 where they express conclusions about trend in terms of the low confidence in this that and the next thing instead of the usual phraseology of accepting or rejecting a null hypothesis.
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The author makes the classic mistake of conflating strong evidence = scientific consensus with what in the case of climate change and Covid-19 is a politically expedient manufactured ‘consensus of scientists’. Judith Curry says it so very well in this essay – which Facebook have censored!
To quote from Judith’s essay:
It’s pretty obvious that the author of your book hasn’t got a clue as to the actual origin of what he dismisses so airily as anti-vaxxer sentiments and climate change denialism. Because what is actually occurring is that certain individuals, independent thinkers, are questioning, quite justifiably, based upon hard data and evidence a lot of the time, the legitimacy of the manufactured consensus of scientists re. Covid-19 vaccination and climate change. The author thinks that the ‘scientific consensus’ itself is based upon irrefutable data and evidence – and settled science- because that is how the manufactured consensus is sold to the gullible public, of which our author is a member, despite his above average education and academic position. His prior is a belief that manufactured consensus = scientific certainty. But if he’s on Facebook, he won’t get the opportunity to reassess his prior belief, because Zuckerberg removed Judy’s excellent post.
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Jaime,
The evidence for climate science being politicised is just one example of the sort of thing that sceptics worry about. Maybe we worry too much, and then again, maybe not. The point is that it is something that we sceptics take into account when updating our beliefs. We are not forming an opinion and then sticking with it come hell or high water. And if we are slow to update our beliefs, then I don’t think we are any more likely to be guilty of this than would be the individual featured in my article.
I think we should also be taking into account the possibility that different people with similar prior beliefs may update them in quite a different way despite being presented with the same new evidence. Take the following podcast, for example:
Like Hossenfelder, my concerns regarding climate science were informed by the malaise that fundamental physics seems to be suffering from, i.e., when there is too much scope for theorising, and little scope for experimental confirmation, the socialising processes that influence the formation of consensus can begin to dominate to the detriment of a field’s integrity. We both see similar concerns regarding climate scientists and, as a result, harbour a certain degree of distrust. However, Hossenfelder concludes that groupthink has led to climate scientists being too conservative in their risk assessments (a conclusion shared by Schellnhuber), whilst I see groupthink that may be leading to an overstated risk. I think both conclusions can be entertained, given the available evidence. Both Hossenfelder and we sceptics are engaging in similar thinking but arriving at different conclusions; however, neither should be accused of acting like a religious fundamentalist — that’s just the lazy labelling that Jit referred to.
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JJ your comment slams it out for a six. You get these effects of institutional imbrication where all parties are aligned in only one direction. Another example is the “blue stack” in America, where the Democratic Party controls, or at least surfs on, an almost total alignment of institutional power, to the extent that an obviously incompetent airhead is now their presidential candidate and yet all organs of power just play along with the entire fake charade. If you show doubt, you’re “far right”. The danger is coordinated institutional control and groupthink within the professional classes (via the mechanisms identified by Judith Curry). It’s totalitarian. And yet, governments love to bleat on about “misinformation” and the supposed dangers of unregulated social media allowing nuts and cranks to have their day. According to institutional.power, there’s no such thing as groupthink, and there can be no possible analysis of it, because actually it’s divine transcendent truth (“The Science”), not a tawdry melange of machine politics and bully tactics. No, in the elevated view of professional-class Guardian readers (who sit above the fray on clouds of infinite wisdom and moral sanctity) it’s all about the supposed dangers of malign incels lurking in corners of the internet brainwashing the ignorant masses.
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Re Hossenfelder and climate change, she sides with the alarmists because she leaves out pertinent evidence contrary to IPCC’s paradigm. Here’s the video where radiation myopia leads her to fall short of the scientific requirement for a theory to explain all the relevant information.
https://www.youtube.com/embed/oqu5DjzOBF8
Chiefio provided an insightful critique which I summarized here:
https://rclutz.com/2023/06/25/sabines-video-myopic-on-ghg-climate-role/
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In my article above I spoke of the philosophy of the empirical sceptic, linking to a previous article I had written on that subject. For those readers who chose not to follow that link, I would like, nevertheless, to quote the linked article’s closing statement. I think it nicely sums up the point I’m trying to make now. It also nicely encapsulates Jit’s point regarding lazy labelling:
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Climate catastrophist George Monbiot is often condemning “climate deniers” and their oil industry funding. so the conclusion of this piece on chronic fatigue syndrome was surprising:
‘https://www.theguardian.com/commentisfree/2024/oct/18/maeve-bothby-oneill-me-chronic-fatigue-syndrome
Here are some things that should not need stating. Scientists and those who champion them should never close ranks against empirical challenge and criticism. They should not deny requests for data, should not shore up disproven claims, should not circle the wagons against legitimate public challenge.
Maybe he would like to contribute to Cliscep.
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Potentilla,
That’s a superb find. Mr Monbiot is quite right, of course, and we here would agree completely with his sentiments. It’s strange, though, how anyone suggesting the same about climate science is quickly labelled a denier and told to move along, there’s nothing to see here.
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